1. Field of the Invention
The present invention relates to computer system backup. More particularly, the present invention relates to a system and method of copying recovery points from one storage system to another.
2. Description of the Related Art
A backup refers to the making of copies of managed data so that the copies can be used to restore the managed data in the event that the managed data is lost. Typically, the managed data is stored in original storage, a primary copy of the managed data is stored in primary storage and a secondary copy of the managed data is stored in secondary storage. For example, the managed data is stored in a client system, the primary copy of the managed data is stored in a media server, and the secondary copy of the managed data is stored in a magnetic tape device.
The primary copy of the managed data stored in primary storage is organized to allow the managed data to be quickly and easily restored. For example, initially and then periodically, a full backup of all of the managed data is taken. After that, an incremental backup of only the managed data that has changed since the previous full or incremental backup is taken.
A recovery point is the state of the managed data at a particular point in time. Stated another way, the recovery point is the managed data existing at a particular point in time that is being protected. Typically, a recovery point is a full backup or a full backup plus incremental backup(s).
Many backup products copy every full and incremental backup from primary storage to secondary storage. As a result, the entire chain of incremental backups is copied.
As a result, in the event that a recovery point must be restored, there is slow restore performance due to the long chain of incremental backups that must be used.
Further, often only particular recovery points of all of the recovery points in primary storage are desired to be copied to secondary storage. Thus, copying the entire chain of incremental backups to secondary storage results in more recovery points being copied to secondary storage than are desired.
Further, if any ancestor full backup or ancestor incremental backup is missing, it may not be possible to restore the recovery point.